ProTech Dampers Adjustment?
Discussion
I bought a set of ProTech adjustable dampers (Series 400?) and springs from Race Tech to replace the old SPAX units on my S1. My intention was to also raise the ride height. When I opened the box I was surprised to find that they're slightly shorter than the SPAX dampers. ??? And the adjustment knob only has eight clicks rather than the thirteen everyone else seem to have. There were no instructions in the packages. I'm guessing that turning the knob clockwise increases the damping. I'm also guessing that the adjustment ring on the tube only changes the preload on the spring and does not change the ride height of the car. There is also quite a size difference in the springs on the Protechs compared with the SPAX. Photo attached. Has anyone out there got a set of these? How did you set them up? 
Setting up springs and dampers is a complex task. Don't take this the wrong way, but from your post I don't get the impression you understand what you're taking on. Are you sure these springs and dampers are even suitable for the car and the ride/handling characteristics that you want?
A couple of other things .. racetech list them as suitable for all S models, but there was a change in trailing arm pickups, and a change for the later V8S front wishbone so I'd question the one size fits all solution. Also, they're 130 pounds more expensive than if you'd bought them from me, so I need to put my prices up, thanks 
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Hi Peter
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Hi Peter
I've spent the last few days exchanging emails across the Atlantic with RaceTech customer service. Nice people. They've contacted ProTech who said the eight click valve adjustment is only for their racing dampers. Why they were installed on these they don't know. The dampers are short because they have the short eyes installed rather than the long eyes. Why? Unknown. Their solution is to send me the 13 click valve parts and longer eyes which I would have to install. I'm not sure I'm comfortable with this as I'd be tampering with the factory assembly, plus it's unlikely the car's ride height would be any higher which was one of my original goals in replacing the 34 year SPAX dampers. (We have the worst roads in the nation and I'm tired of occasionally grounding out with two people in the car.) There's also the fact that I'd have to experiment with the spring tension which can be time consuming and, at times, risky. So, I'm considering just shipping them back and chalking it up to yet another expensive TVR misadventure. The problem is finding a set of dampers that are compatible with the S1 and are a direct replacement without a lot of rocket science in setting them up. I found a set of GAZ, supposedly for the TVR S, on sale, but the company wouldn't ship to the US. I tried contacting Dominion Spares on this side of the pond for a set of Koni dampers but got no answers from emails or phone calls. Racing Green sells front and rear SPAX dampers and replacement springs, but, again, big money and high shipping / return costs if they're not right. So, the original SPAX unit is going back on the car to make it roadworthy, more or less, so I can shift to working out all the other problems I've discovered, or sell it and get an MG. Time will tell. Thanks for your inputs.
If you don't consider them fit for your purpose, and you ordered a direct fit replacement which you don't consider to be direct fit because of the length difference, then you could send them back.
Then go to a USA based damper manufacturer and tell them exactly what you require, give them the info they require (they will probably ask you to measure motion ratios and weigh the car) and then at least if what you receive isn't quite what you require you are dealing with a manufacturer in your own country, which should make things slightly easier? Try and choose a manufacturer close to where you live, i appreciate the USA is a BIG place.
Then go to a USA based damper manufacturer and tell them exactly what you require, give them the info they require (they will probably ask you to measure motion ratios and weigh the car) and then at least if what you receive isn't quite what you require you are dealing with a manufacturer in your own country, which should make things slightly easier? Try and choose a manufacturer close to where you live, i appreciate the USA is a BIG place.
LoFlyer said:
I've spent the last few days exchanging emails across the Atlantic with RaceTech customer service. Nice people. They've contacted ProTech who said the eight click valve adjustment is only for their racing dampers. Why they were installed on these they don't know. The dampers are short because they have the short eyes installed rather than the long eyes. Why? Unknown. Their solution is to send me the 13 click valve parts and longer eyes which I would have to install. I'm not sure I'm comfortable with this as I'd be tampering with the factory assembly, plus it's unlikely the car's ride height would be any higher which was one of my original goals in replacing the 34 year SPAX dampers. (We have the worst roads in the nation and I'm tired of occasionally grounding out with two people in the car.) There's also the fact that I'd have to experiment with the spring tension which can be time consuming and, at times, risky. So, I'm considering just shipping them back and chalking it up to yet another expensive TVR misadventure. The problem is finding a set of dampers that are compatible with the S1 and are a direct replacement without a lot of rocket science in setting them up. I found a set of GAZ, supposedly for the TVR S, on sale, but the company wouldn't ship to the US. I tried contacting Dominion Spares on this side of the pond for a set of Koni dampers but got no answers from emails or phone calls. Racing Green sells front and rear SPAX dampers and replacement springs, but, again, big money and high shipping / return costs if they're not right. So, the original SPAX unit is going back on the car to make it roadworthy, more or less, so I can shift to working out all the other problems I've discovered, or sell it and get an MG. Time will tell. Thanks for your inputs.
you can visit Protecs Hompeage and "built you own shock"...you can choose the damper length, the spring rates etc.this said, dampers with adjustable spring-seats are mainly for adjusting pre-load (corner weight). obviously, depending on the spring-rate choosen, you also may be able to "adjust"a bit the ride-height.
its quite complex.
for example: if yu use a stiffer sping, the weight of the car wont compress the spring as much as a softer one = higher ride-height, but in the same moment a harsher ride.
A positive note. Bill at Dominion Spares in Virginia has responded, confirming he did not perish from COVID-19. He has in the past fitted GAZ shocks successfully to an S1 and is searching for his notes. Which brings up the question, where can I find the numbers for spring rates, etc applicable to a 1988 TVR S1?
I am going to change the dampers on J-LLO as the existing units on J-LLO look like they need yet another rebuild. I was thinking of Protechs but this conversation has put me off a little. The other, vaguely affordable option would be Gaz Gold Pro. The suspension wiki is Ok but does not give much in the way of the longer term reliability of these options. The car is used exclusively on road with no track days so looking for a reasonably comfortable ride with one or two heavier occupants. Advise would be most welcome.
Protech will do what ever you need damper wise, and they are good value for money and If they have not worked for anyone I suspect they where badly specified in the first place.
Generally speaking basic setting up of dampers is not as hard as made out. Fit one on the dampers without a spring and see how much suspension travel you have with the wheel fitted between the suspension full drop with a trolley jack lifting the chassis and full compression as you lower the car towards the ground. if you have a couple of inches travel each side of the normal ride height position you are going to be OK unless you have soft springs or are going off road. Once the springs are refitted, ride height needs to be set uniformly around the car by winding the springs up or down until the car sits level with the correct wheel arch gaps. Altering one spring will change all 4 heights so its a tedious process to get it spot on as you go around all 4 springs repeatedly. Once you have done this the basic damper setting can be adjusted- simply bounce each side of the car down by hand and see if it oscillates up and down. You need each corner to bounce up once and just start to compress slightly again as a starting point. I personally set the dampers to give the same rebound on all 4 corners, not simply say by the number of clicks, as the cars weight distribution may not be uniform across all 4 wheels and its important the car rebounds uniformly to remain stable. This is rule of thumb for road use, as purists will talk about setting corner weights with spring height with the driver on board which is more critical for race use, but this will get you going for the road.
Generally speaking basic setting up of dampers is not as hard as made out. Fit one on the dampers without a spring and see how much suspension travel you have with the wheel fitted between the suspension full drop with a trolley jack lifting the chassis and full compression as you lower the car towards the ground. if you have a couple of inches travel each side of the normal ride height position you are going to be OK unless you have soft springs or are going off road. Once the springs are refitted, ride height needs to be set uniformly around the car by winding the springs up or down until the car sits level with the correct wheel arch gaps. Altering one spring will change all 4 heights so its a tedious process to get it spot on as you go around all 4 springs repeatedly. Once you have done this the basic damper setting can be adjusted- simply bounce each side of the car down by hand and see if it oscillates up and down. You need each corner to bounce up once and just start to compress slightly again as a starting point. I personally set the dampers to give the same rebound on all 4 corners, not simply say by the number of clicks, as the cars weight distribution may not be uniform across all 4 wheels and its important the car rebounds uniformly to remain stable. This is rule of thumb for road use, as purists will talk about setting corner weights with spring height with the driver on board which is more critical for race use, but this will get you going for the road.
TurboTony said:
I am going to change the dampers on J-LLO as the existing units on J-LLO look like they need yet another rebuild. I was thinking of Protechs but this conversation has put me off a little. The other, vaguely affordable option would be Gaz Gold Pro. The suspension wiki is Ok but does not give much in the way of the longer term reliability of these options. The car is used exclusively on road with no track days so looking for a reasonably comfortable ride with one or two heavier occupants. Advise would be most welcome.
I replaced those Avo's you now have with Protech, been faultless Tony, couldn't be happier with them.TurboTony said:
Thanks Mike. Good to hear that they have been trouble free. Seems that they are only listed by Racetech unless other suppliers can sell them?
That's where mine came from back in 2011 !Think there was an offer on at the time, part number RD6B "front and rear adjustable dampers c/w springs all S models"
Funnily enough spoke to them at the Kit Car Show last Monday about getting them serviced
OP is the new shock definitely fully extended? You want the car to ride higher, you have a lot of thread to adjust to a higher (longer than your old shock), if the shock isn't already fully extended.
Sorry if this is obvious but I haven't seen you mention whether that's the case. If it's going to be expensive to return these shocks, I'd certainly try fitting them first, because they could be just fine. Protech have a decent reputation.
I'd try turning the collar on the thread, and see if it extends the shock.
Sorry if this is obvious but I haven't seen you mention whether that's the case. If it's going to be expensive to return these shocks, I'd certainly try fitting them first, because they could be just fine. Protech have a decent reputation.
I'd try turning the collar on the thread, and see if it extends the shock.
DuncanM said:
I'd try turning the collar on the thread, and see if it extends the shock.
The problem is that getting the right spring rates, damper length, damper rates, ride height, geometry at that ride height and so on is a complicated process. In a way it's unfortunate that it is so trivially easy to bolt the wrong components on or bolt the right components with the wrong adjustments.GreenV8S said:
The problem is that getting the right spring rates, damper length, damper rates, ride height, geometry at that ride height and so on is a complicated process. In a way it's unfortunate that it is so trivially easy to bolt the wrong components on or bolt the right components with the wrong adjustments.
Oh I'm surprised you say that, in my limited experience, coilovers are much nicer, and easier to install than normal damper and spring.Spring rates are typically a personal preference, I run 600lbs front and rear on my Cerb and love it. I previously ran 400F 325R and that was good too. There's a lot of variation with TVRs, and no exact right or wrong.
My point was more that the OP mentioned it being a costly mistake to send them back, when they might actually be great at doing the job he wants - not bottoming out, and higher ride height.
Obviously the damper needs to extend to satisfy the requirement
The answer is "yes", I turned the spring collar up about 2 inches on one of the ProTechs to make sure the rod was fully extended. Measuring bolt center to center they're about .75" short compared to the SPAX. Since it will take about three months or more to get the GAZ units made and delivered, and considering the cost of return shipping, I've decided to keep the ProTechs. RaceTech is sending the valve parts (13 clicks) and the extended eyes which should make them roughly equivalent in extended length to the SPAX units. I'm going to assume the springs are correct for the application. The old SPAX springs are almost fully compressed with two people in the car, so anything is bound to be better. This is not going to be a track car so I'll set up the corner weights accordingly using the information provided above. As for ride height, it is what it is after adjusting the springs. If it's acceptable I may cancel the GAZ order.
LoFlyer said:
The answer is "yes", I turned the spring collar up about 2 inches on one of the ProTechs to make sure the rod was fully extended. Measuring bolt center to center they're about .75" short compared to the SPAX. Since it will take about three months or more to get the GAZ units made and delivered, and considering the cost of return shipping, I've decided to keep the ProTechs. RaceTech is sending the valve parts (13 clicks) and the extended eyes which should make them roughly equivalent in extended length to the SPAX units. I'm going to assume the springs are correct for the application. The old SPAX springs are almost fully compressed with two people in the car, so anything is bound to be better. This is not going to be a track car so I'll set up the corner weights accordingly using the information provided above. As for ride height, it is what it is after adjusting the springs. If it's acceptable I may cancel the GAZ order.
That's good to hear, hopefully you get a good solution without having to spend more money and time Gassing Station | S Series | Top of Page | What's New | My Stuff